Semiconductor laser device and manufacturing method thereof, and submount manufacturing method

ABSTRACT

A semiconductor laser device can include an insulating single crystal SiC having a first surface, a second surface, and micropipes having openings in the first surface and the second surface. A conductive base can be provided on a side of the first surface of the single crystal SiC, and a semiconductor laser element can be provided on a side of the second surface of the single crystal SiC. An insulating member can be formed in the micropipes.

TECHNICAL FIELD

The present disclosure relates to a semiconductor laser device that usesa single crystal silicon carbide (SiC) as a submount.

BACKGROUND

A member with superior heat dissipation is favorably used as a submountof a semiconductor laser device (Japanese Patent Application Laid-openNo. 2008-135629). Known examples of a member with superior heatdissipation include a single crystal SiC.

However, a plurality of pieces for submounts that are cut out from asingle crystal SiC wafer include those having a hollow pipe-like defectreferred to as a micropipe. When a micropipe is penetrated by aconductive member such as solder material, the insulating property ofthe single crystal SiC is destroyed and a semiconductor laser deviceusing such a single crystal SiC becomes a defective product.

SUMMARY

In consideration thereof, an object of one embodiment is to provide asemiconductor laser device using a single crystal SiC whose yield isimproved by suppressing a decline in insulating property that isattributable to micropipes as a submount, a method of manufacturing thesemiconductor laser device, and a method of manufacturing the submount.

According to one embodiment, a semiconductor laser device including: aninsulating single crystal SiC having a first surface, a second surface,and micropipes having openings in the first surface and the secondsurface; a conductive base provided on a side of the first surface ofthe single crystal SiC; a semiconductor laser element provided on a sideof the second surface of the single crystal SiC; and an insulatingmember disposed in the micropipes.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are schematic diagrams showing a general configurationof a semiconductor laser device according to an embodiment, wherein FIG.1A is a perspective view and FIG. 1B is a cross section taken along A-Ain FIG. 1A (a cutaway view from a semiconductor laser element 30 to abase 20 along a short direction of the semiconductor laser element 30);

FIGS. 2A, 2B, 2C, 2D, and 2E are schematic diagrams showing an exampleof a method of manufacturing a submount according to an embodiment; and

FIGS. 3A and 3B are schematic diagrams showing an example of a method ofmanufacturing a semiconductor laser device according to an embodimentwhich uses a submount formed by steps shown above.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIGS. 1A and 1B are schematic diagrams showing a general configurationof a semiconductor laser device according to an embodiment. FIG. 1A is aperspective view and FIG. 1B is a cross section taken along A-A in FIG.1A (a cutaway view from a semiconductor laser element 30 to a base 20along a short direction of the semiconductor laser element 30).

As shown in FIGS. 1A and 1B, a semiconductor laser device 1 according toan embodiment includes: an insulating single crystal SiC 10 having afirst surface 11, a second surface 12, and micropipes 15 having openingsin the first surface 11 and the second surface 12; a conductive base 20provided on a side of the first surface 11 of the single crystal SiC 10;a semiconductor laser element 30 provided on a side of the secondsurface 12 of the single crystal SiC 10; and an insulating member 40 adisposed in the micropipes 15.

The single crystal SiC 10 can be used as a submount. The submount is,for example, a member that is provided between the base 20 and thesemiconductor laser element 30. Since the single crystal SiC 10 hassuperior heat dissipation as described earlier, the single crystal SiC10 can be particularly favorably used as a submount of a semiconductorlaser device using a high-output semiconductor laser element thatgenerates a large amount of heat.

As an example of the single crystal SiC 10, an insulating single crystalSiC is used which has sufficient resistance to prevent a conductive part(for example, a base) that is provided on one surface thereof and aconductive part (for example, a semiconductor laser element) that isprovided on the other surface thereof, from leaking. A single crystalSiC with specific resistance that equals or exceeds 1×10⁷ Ω·cm may beused.

A shape of the single crystal SiC 10 is not particularly limited.Examples of the shape of the single crystal SiC 10 include a cuboid anda triangular prism.

A thickness of the single crystal SiC 10 is not particularly limited.However, for example, the thickness of the single crystal SiC 10 may beset to 100 μm or more since the single crystal SiC 10 is subjected to aload due to a difference in thermal expansion coefficients when thesingle crystal SiC 10 is bonded with the semiconductor laser element 30and the base 20 and from the perspective of easiness of handling duringmanufacturing processes. In addition, by setting the thickness of thesingle crystal SiC 10 so as to exceed the thickness of the semiconductorlaser element 30, heat from the semiconductor laser element 30 can beradiated in an efficient manner.

Moreover, when the thickness of the single crystal SiC 10 is equal to orless than 400 μm, since a distance between the first surface 11 and thesecond surface 12 of the single crystal SiC 10 is short, the insulatingproperty is easily destroyed once a conductive member penetrates intothe micropipes 15. Therefore, yield of a conventional semiconductorlaser device using the single crystal SiC 10 with a thickness of 400 μmor less as a submount is not always favorable. However, according to thepresent embodiment, since the insulating property of the single crystalSiC 10 improves due to the insulating member 40 a disposed in themicropipes 15, the yield of a semiconductor laser device using thesingle crystal SiC 10 with a thickness of 400 μm or less as a submountcan be improved.

The micropipes 15 are mainly hollow pipe-like defects that extend in acrystal growth direction (a direction perpendicular to a C surface of acrystal) of the single crystal SiC 10. However, not all micropipesextend in a constant direction, and there may be micropipes that extenddiagonally with respect to the C surface.

The micropipes 15 include micropipes that penetrate and micropipes thatdo not penetrate the single crystal SiC 10. Micropipes that do notpenetrate the single crystal SiC 10 have openings in at least one of thefirst surface 11 and the second surface 12 of the single crystal SiC 10in a similar manner to micropipes that penetrate the single crystal SiC10. However, the micropipes 15 that penetrate the single crystal SiC 10have openings in both of the first surface 11 and the second surface 12of the single crystal SiC 10. Moreover, while the insulating member 40 ais disposed in the micropipes 15 that penetrate the single crystal SiC10, the insulating member 40 a may or may not be disposed in themicropipes 15 that do not penetrate the single crystal SiC 10.

A diameter of the micropipes 15 ranges from, for example, around 0.1 μmto 100 μm. The present embodiment can be applied to the micropipes 15having various diameters. However, a conductive member (bonding members50 a and 50 b) such as solder is provided on at least one of the firstsurface 11 and the second surface 12 of the single crystal SiC 10, andsuch a member conceivably penetrates into the micropipes 15 due to acapillary phenomenon. Therefore, the present embodiment can beparticularly favorably applied to the micropipes 15 with a smalldiameter which is more affected by a capillary phenomenon. Specifically,the present embodiment can be particularly favorably applied to themicropipes 15 with a diameter ranging from around 0.1 μm to 30 μm.

According to the present embodiment, even if a plurality of pieces forsubmounts that are cut out from a single crystal SiC wafer include alarge number of those having a hollow pipe-like defect referred to as amicropipe (for example, included in a proportion of around 50%), sincethe insulating property of the single crystal SiC 10 is improved by theinsulating member 40 a disposed in the micropipes 15, the yield of asemiconductor laser device using the single crystal SiC 10 as a submountcan be improved.

The base 20 can be provided on the side of the first surface 11 of thesingle crystal SiC 10. A conductive member such as copper, iron, andalloys thereof can be used for the base 20 so as to enable heatgenerated by the semiconductor laser element 30 to be released in anefficient manner.

When providing the base 20 on the side of the first surface 11 of thesingle crystal SiC 10, for example, the bonding member 50 a that bondsthe base 20 and the first surface 11 to each other can be used. Aconductive member such as a solder material or a silver paste is used asthe bonding member 50 a so as to enable heat generated by thesemiconductor laser element 30 to be released in an efficient manner.

The semiconductor laser element 30 can be provided on the side of thesecond surface 12 of the single crystal SiC 10.

When providing the semiconductor laser element 30 on the side of thesecond surface 12 of the single crystal SiC 10, for example, a metallayer 60 made of titanium, nickel, palladium, platinum, gold, and/orcopper is provided on the second surface 12 of the single crystal SiC 10and the semiconductor laser element 30 is mounted on the metal layer 60.While the semiconductor laser element 30 can be mounted by bonding usinga bonding member (examples: a solder material such as AuSn, a conductiveadhesive such as silver paste, and a metallic bump such as a gold bump),FIG. 1B shows a mode in which the semiconductor laser element 30 ismounted using the bonding member 50 b as an example. Moreover, whenusing a member with high fluidity such as solder as the bonding member,it is conceivable that the conductive material can also readilypenetrate into the micropipes 15 from the second surface 12. Therefore,in such a case, the insulating member 40 a is favorably provided fromone end to another end in the micropipes 15.

Various semiconductor laser elements such as GaN-based or GaAs-basedsemiconductor laser elements can be used as the semiconductor laserelement 30. However, a difference in thermal expansion coefficientsbetween GaN and the single crystal SiC 10 is small, and a GaN basedsemiconductor laser has a higher drive voltage than a GaAs basedsemiconductor laser and generates heat more readily. Therefore, thepresent embodiment which uses the single crystal SiC 10 with high heatdissipation as a submount is suitable for a semiconductor laser deviceusing a GaN semiconductor laser element. Moreover, in order to securesuperior heat dissipation, the semiconductor laser element 30 isfavorably mounted in an area where the insulating member 40 a is notdisposed.

In addition to low-output (for example, equal to or lower than 0.5 W)semiconductor laser elements, high-output (for example, equal to orhigher than 1 W and more particularly equal to or higher than 3.5 W)semiconductor laser elements can be used as the semiconductor laserelement 30. Since a high-output semiconductor laser element generatesmore heat than a low-output semiconductor laser element, the presentembodiment which uses the single crystal SiC 10 with high heatdissipation as a submount is suitable for a semiconductor laser deviceusing a high-output semiconductor laser element.

The insulating member 40 a is disposed in the micropipes 15.Accordingly, since conductive members such as the bonding members 50 aand 50 b are less likely to penetrate into the micropipes 15 from theside of the first surface 11 or the side of the second surface 12 of thesingle crystal SiC 10, the insulating property of the single crystal SiC10 is improved.

Moreover, the closer the conductive member on the side of the firstsurface 11 and the conductive member on the side of the second surface12 are to each other, the more easily an insulation breakdown of thesingle crystal SiC 10 occurs. An insulation breakdown may occur not onlywhen the conductive member on the side of the first surface 11 and theconductive member on the side of the second surface 12 are connected toeach other, but also when the conductive member on the side of the firstsurface 11 and the conductive member on the side of the second surface12 are separated from but close to each other. Accordingly, the insideof the micropipes 15 is favorably completely filled in a gapless mannerby the insulating member 40 a so as to eliminate space that allowspenetration of a conductive member such as the bonding members 50 a and50 b.

However, even if a gap exists, the conductive member on the side of thefirst surface 11 and the conductive member on the side of the secondsurface 12 can be prevented from penetrating deeply into the micropipes15 as long as the insulating member 40 a is present. Therefore, theconductive member on the side of the first surface 11 and the conductivemember on the side of the second surface 12 are more separated from eachother as compared to a case where the insulating member 40 a is notprovided.

Accordingly, even in a case where the inside of the micropipes 15 is notcompletely filled by the insulating member 40 a and a gap is present(for example, when there are gaps in around 80% to 90% of a capacity ofthe micropipes 15), the insulating property of the single crystal SiC 10can be improved. When a gap is present, the insulating member 40 a isfavorably provided with a gap from the side of the first surface 11 tothe side of the second surface 12 of the micropipes 15 (the insulatingmember 40 a is distributed from one end to the other end of themicropipes 15). Accordingly, the conductive members can be preventedfrom deeply penetrating into the micropipes 15.

Moreover, for example, an insulation breakdown test performed byrespectively providing conductive members on both surfaces of a singlecrystal SiC with a thickness of approximately 200 μm and a measurementof a voltage where an insulation breakdown occurs and a distance betweenone conductive member and the other conductive member revealed acorrelation between the two and confirmed that insulation breakdownvoltage tends to decline as the distance between conductive membersdecreases. This tendency was confirmed by plotting a relationshipbetween insulation breakdown voltage and distances between conductivemembers for a plurality of samples on a graph representing insulationbreakdown voltage on an abscissa and the distance between conductivemembers on an ordinate. Specifically, distances between conductivemembers were plotted on the graph described above for insulationbreakdown voltages of 500 V, 700 V, 800 V, 900 V, and 1000 V, and alinear approximation line was drawn using a median of the distancebetween conductive members for each insulation breakdown voltage.

From the graph, the insulation breakdown voltage can conceivably be setto 250 V or higher if the distance between conductive members is 15 μmor more. However, since the insulation breakdown voltage is favorablyset to 250 V or higher, the insulating member 40 a that enables adistance between conductive members of 15 μm or more to be secured isfavorably provided to obtain further superior insulating property. Inaddition, it is expected from the graph described above that aninsulation breakdown does not occur until 500 V if the distance betweenconductive members is 30 μm or more. However, in a more favorable mode,in order to secure an insulation breakdown voltage of 500 V so as toincrease withstand voltage of the single crystal SiC 10, the distancebetween conductive members is set to 30 μm or more, in which range it isexpected that an insulation breakdown voltage of 500 V can be secured.

In this case, an insulation breakdown voltage is a voltage where acurrent suddenly starts to flow when voltage is increased in stages. Inaddition, the distance between conductive members refers to a shortestdistance between the conductive member on the side of one surface andthe conductive member on the side of the other surface. Since theshortest distance between the conductive members is reduced when a partof at least any one of the conductive member on the side of one surfaceand the conductive member on the side of the other surface penetratesinto a micropipe, the shortest distance between the conductive memberscan be typically obtained by measuring a distance between conductivemembers in the micropipe. For example, the distance between conductivemembers can be measured by an X-ray photograph taken from a sidewisedirection of a single crystal SiC.

When heat dissipation of the insulating member 40 a is lower than thatof the single crystal SiC 10, the first surface 11 and/or second surface12 of the single crystal SiC 10 favorably has an area where theinsulating member 40 a is not disposed and, more favorably, an entirearea of the first surface 11 and/or second surface 12 of the singlecrystal SiC 10 is an area where the insulating member 40 a is notdisposed. As a result, heat dissipation of the semiconductor laserdevice 1 can be improved.

Moreover, among the first surface 11 and the second surface 12 of thesingle crystal SiC 10, since the second surface 12 is the surface onwhich the semiconductor laser element 30 is provided, heat stagnation ismore likely to occur than on the side of the first surface 11 that isthe surface on which the base 20 is provided. Therefore, when there is adifference in amounts of the insulating member 40 a between one surfaceand the other surface of the single crystal SiC 10, the surface with agreater amount of the insulating member 40 a is favorably set as thefirst surface 11 that is the surface on which the base 20 is providedand the surface with a smaller amount of the insulating member 40 a isfavorably set as the second surface 12 that is the surface on which thesemiconductor laser element 30 is provided.

A member made of an insulating material such as silicon oxide (SiO₂) oraluminum oxide (Al₂O₃) is used as the insulating member 40 a.Alternatively, an insulating material such as silicon resin or epoxyresin may be used. When using a resin, a thermosetting resin isfavorably used so as to prevent the resin from being melted by heat whenthe single crystal SiC 10 is bonded to the base 20 or the semiconductorlaser element 30. In addition, since the higher the output of thesemiconductor laser element 30, the more readily dust accumulation dueto laser light occurs when using an organic substance, an inorganicsubstance such as SiO2 is favorably used to prevent dust accumulation.

As described above, according to the present embodiment, since theinsulating member 40 a is disposed in the micropipes 15 of the singlecrystal SiC 10, the conductive member on the side of the first surface11 or the conductive member on the side of the second surface 12 isprevented from penetrating into the micropipes 15 and, even if suchpenetration occurs, the conductive member on the side of the firstsurface 11 and the conductive member on the side of the second surface12 can be further separated from each other compared to a case where theinsulating member 40 a is not provided. Therefore, according to thepresent embodiment, the yield of a semiconductor laser device that usesthe single crystal SiC 10 as a submount can be improved by suppressing adecline in insulating property attributable to the micropipes 15.

FIGS. 2A to 2E are schematic diagrams showing an example of a method ofmanufacturing a submount according to the present embodiment.Hereinafter, a description will be given with reference to FIGS. 2A to2E.

First, as shown in FIG. 2A, while orienting one surface 13 of the singlecrystal SiC 10 in a direction that differs from a side where a jig 100is present, the other surface 14 of the single crystal SiC 10 and thejig 100 are oriented so as to face each other and the insulating singlecrystal SiC 10 is placed on the jig 100. The jig 100 is an adsorptiontable or the like that is a stand on which the single crystal SiC 10 isplaced.

A cavity X is provided in the jig 100 to facilitate adsorption of thesingle crystal SiC 10. For example, as shown in FIG. 2A, performingsuction by providing the cavity X so that a depression is formed on thejig 100 and an outer edge of the single crystal SiC 10 comes intocontact with the jig 100 causes pressure in the cavity X to drop. As aresult, the single crystal SiC 10 can be fixed in a stable manner.

Moreover, an opening area of the cavity X can be set to, for example,around 98% (a proportion based on an area of the other surface 14) ofthe single crystal SiC 10. In this case, for example, around 97% (aproportion based on the area of the other surface 14) of the singlecrystal SiC 10 can be used as a submount. Accordingly, since around 1%(a proportion based on an area of the other surface 14) of the singlecrystal SiC 10 is removed without being used (97%=98%−1%: bothproportions based on the area of the other surface 14), only a portionthat is sufficiently adsorbed is used as a submount.

Next, as shown in FIG. 2B, a fluid object 40 b containing an insulatingmaterial is applied to the one surface 13 of the single crystal SiC 10.For example, a solvent (such as an organic solvent) in which aninsulating material is dissolved is used as the fluid object 40 b (suchas spin-on glass).

Next, as shown in FIG. 2C, the other surface 14 of the single crystalSiC 10 is adsorbed by the jig 100. Accordingly, the applied fluid object40 b is sucked from the other surface 14 of the single crystal SiC 10into the micropipes 15. At this point, suction is favorably performeduntil the fluid object 40 b reaches the other surface 14.

Next, as shown in FIG. 2D, the sucked fluid object 40 b is hardened inthe micropipes 15. Thus, the hardened fluid object 40 b is obtained asthe insulating member 40 a. For example, when spin-on glass is used asthe fluid object 40 b, the fluid object 40 b is dried to volatilize thesolvent (a part of the fluid object 40 b) and baked at a highertemperature than the drying temperature. Accordingly, pyrolysis of ametal organic compound starts during the baking, and a metal oxide(SiO2) is formed. In this case, SiO2 is formed in the micropipes 15 asthe insulating member 40 a.

Moreover, when a part of the fluid object 40 b is volatilized asdescribed above, the volume of the insulating member 40 a is reduced ascompared to the state of the fluid object 40 b. Therefore, for example,a state where gaps occupying around 80% to 90% of the capacity of themicropipes 15 exists in the micropipes 15 instead of a state where themicropipes 15 is completely filled with the insulating member 40 a in agapless manner. However, as described earlier, the insulating propertyof the single crystal SiC 10 is improved even in such a state.

Next, as shown in FIG. 2E, the insulating member 40 a (in other words,the insulating member 40 a which is not sucked into the micropipes 15and which remains outside of the micropipes 15) formed on the onesurface 13 and/or the other surface 14 of the single crystal SiC 10 isremoved. Accordingly, an area where the insulating member 40 a is notformed is provided on the one surface 13 and/or the other surface 14 ofthe single crystal SiC 10. Generally, since heat dissipation of theinsulating member 40 a is lower than that of the single crystal SiC 10,heat dissipation of the semiconductor laser device 1 is improved byproviding such an area where the insulating member 40 a is not formed.

Moreover, when removing a part of the insulating member 40 a, theinsulating member 40 a is to be formed on the one surface 13 and/or theother surface 14 of the single crystal SiC 10. In this case, thethickness of the insulating member 40 a is favorably set to 1 μm orless. As described earlier, generally, since heat dissipation of theinsulating member 40 a is lower than that of the single crystal SiC 10,heat dissipation of the semiconductor laser device 1 is improved byadopting such a configuration.

When removing the insulating member 40 a, a method is favorably used inwhich the insulating member 40 a is preferentially removed (removed at afaster rate) than the single crystal SiC 10. Accordingly, since theremoval of the insulating member 40 a is promoted while removal of thesingle crystal SiC 10 is suppressed, only the insulating member 40 a canbe removed as much as possible without removing the single crystal SiC10.

Examples of such a method include performing wet etching using asolution by which the insulating member 40 a is more likely to beremoved (removed at a greater etching rate) than the single crystal SiC10. As such a solution, for example, when the insulating member 40 a isSiO2, an alkaline solution is favorably used. Specifically, a KOH(potassium hydroxide) solution or a NaOH (sodium hydroxide) solution isfavorably used.

Another example of the method described above involves performingmechanical polishing using abrasive grains by which the insulatingmember 40 a is more likely to be removed (removed at a greater removalrate) than the single crystal SiC 10. For example, silica (SiO2) isfavorably used as the abrasive grains. Using the mechanical polishing,only the insulating member 40 a formed on the one surface 13 and/or theother surface 14 of the single crystal SiC 10 can be removed withoutremoving the insulating member 40 a formed in the micropipes 15.

Yet another example of the method described above is chemical mechanicalpolishing (CMP) that uses both the solution described above and theabrasive grains described above. Using CMP, since a flatter surface canbe obtained, the base 20, the semiconductor laser element 30, and thelike can be more readily fixed to the one surface 13 and/or the othersurface 14 of the single crystal SiC 10 in a stable manner. In addition,using CMP, since the removal amount of the single crystal SiC 10 can bereduced in comparison to mechanical polishing, film thickness variationof the single crystal SiC 10 can be reduced. Furthermore, since damagedue to polishing can be reduced, adhesion with the bonding members 50 aand 50 b can be improved.

With the method of manufacturing a submount according to the presentembodiment described above, since the fluid object 40 b to become theinsulating member 40 a is first applied to one surface 13 of the singlecrystal SiC 10 and the other surface 14 of the single crystal SiC 10 issubsequently adsorbed by the jig 100, the insulating member 40 a can beaccurately formed in the micropipes 15 in a shorter period of time(around several minutes) as compared to a method of forming theinsulating member 40 a in the micropipes 15 by CVD or thermal oxidation.Therefore, the method of manufacturing a submount according to thepresent embodiment is suitable for mass production of the semiconductorlaser device 1 according to the present embodiment. In addition, sincethe fluid object 40 b is fed into the micropipes 15 by adsorption, evenwhen the micropipes 15 extend in an inclined direction with respect to aprimary surface or the micropipes 15 bend inside the single crystal SiC10, the insulating member 40 a can be formed inside the micropipes 15.

Moreover, while the single crystal SiC 10 used in the steps describedabove may be in a state after being cut out from a wafer to be used as asubmount, the single crystal SiC 10 is more favorably in a wafer stateprior to being cut. This is because a wafer state is more suitable formass production.

A wafer state is also more suitable for the single crystal SiC 10 thatis used in the steps described above because a portion of the singlecrystal SiC 10 that comes into contact with the jig 100 (the 2% portionreferred to in the description of the first step) is not adsorbed by thejig 100 and the insulating member 40 a is not formed in the micropipes15 in this portion.

In other words, since performing the steps described above using thesingle crystal SiC 10 in a wafer state enables pieces to be used assubmounts to be cut out while excluding an outer edge portion (the 2%portion referred to in the description of the first step) which had beenin contact with the jig 100, only an area in which the insulating member40 a is formed can be used as submounts. A dicing step is favorablyperformed after the fourth step described earlier in which the fluidobject 40 b is hardened. Furthermore, since the fifth step describedearlier can be performed more efficiently in a wafer state than in adiced state, the dicing step is more favorably performed after the fifthstep.

Moreover, as described above, the present embodiment is configured sothat only a portion that has been sufficiently sucked is used assubmounts by cutting out submounts while excluding an area created byfurther adding a margin of 1% to the outer edge portion (the 2% portionreferred to in the description of the first step) which had been incontact with the jig 100.

FIGS. 3A and 3B are schematic diagrams showing an example of a method ofmanufacturing a semiconductor laser device according to the presentembodiment which uses a submount formed by the steps described above.

After the steps described earlier, for example, the other surface 14 ofthe single crystal SiC 10 which had been adsorbed by the jig 100 can beused as the second surface 12 of the single crystal SiC 10 and thesemiconductor laser element 30 can be provided on the side of thissurface, and the one surface 13 of the single crystal SiC 10 on whichthe fluid object 40 b had been applied can be used as the first surface11 of the single crystal SiC 10 and the base 20 can be provided on theside of this surface.

This can be performed by, for example, as shown in FIG. 3A, providingthe metal layer 60 on the other surface 14 (the second surface 12) ofthe single crystal SiC 10, providing the conductive bonding members 50 aand 50 b in a solid state on the other surface 14 (the second surface12) and the one surface 13 (the first surface 11) of the single crystalSiC 10, placing the one surface 13 (the first surface 11) of the singlecrystal SiC 10 on the heated base 20, and placing the semiconductorlaser element 30 on the other surface 14 (the second surface 12) of thesingle crystal SiC 10.

Accordingly, as shown in FIG. 3B, the bonding members 50 a and 50 b thathad been in a solid state are melted by the heat of the base 20 and thebase 20 is bonded to a side of the one surface 13 (the first surface 11)of the single crystal SiC 10, and, at the same time of or just before orafter the bonding, the semiconductor laser element 30 is bonded to aside of the other surface 14 (the second surface 12) of the singlecrystal SiC 10.

Therefore, the conductive base 20 is fixed to a side of the one surface13 (the first surface 11) of the single crystal SiC 10 and thesemiconductor laser element 30 is provided on a side of the othersurface 14 (the second surface 12) of the single crystal SiC 10.

Moreover, in a departure from the steps described earlier, it is alsopossible to use the other surface 14 of the single crystal SiC 10 whichhad been adsorbed by the jig 100 as the first surface 11 of the singlecrystal SiC 10 and provide the base 20 on the side of this surface, andto use the one surface 13 of the single crystal SiC 10 on which thefluid object 40 b had been applied as the second surface 12 of thesingle crystal SiC 10 and provide the semiconductor laser element 30 onthe side of this surface.

However, as shown in FIG. 2D, since the one surface 13 of the singlecrystal SiC 10 is a surface on which the fluid object 40 b is applied,the amount of the insulating member 40 a tends to exceed that on theother surface 14 of the single crystal SiC 10 unless the insulatingmember 40 a is appropriately removed.

Therefore, as described earlier, favorably, the other surface 14 of thesingle crystal SiC 10 which had been adsorbed by the jig 100 is used asthe second surface 12 of the single crystal SiC 10 and the one surface13 of the single crystal SiC 10 on which the fluid object 40 b had beenapplied is used as the first surface 11 of the single crystal SiC 10.

Accordingly, among the one surface 13 and the other surface 14 of thesingle crystal SiC 10, the surface with a larger amount of theinsulating member 40 a is provided with the base 20 and the surface witha smaller amount of the insulating member 40 a (including a surface onwhich the insulating member 40 a is not formed at all) is provided withthe semiconductor laser element 30.

Moreover, while the single crystal SiC 10 is used as a submount of thesemiconductor laser device 1 in the present embodiment, the singlecrystal SiC 10 can also be used in devices other than a semiconductorlaser device such as an LED device. However, since a semiconductor laserelement differs from an LED element in that an area of a light emittingregion among an area of the entire element is extremely small, heattends to concentrate in the light emitting region. Therefore, higherheat dissipation is demanded. For this reason, a single crystal SiC thatis a material with superior thermal conductivity is conceivablyparticularly suitable as a submount (heat sink) on which a semiconductorlaser element is mounted.

While an embodiment has been described above, the descriptions simplyrelate to one example of the present invention. The present invention isby no means limited by the descriptions.

DENOTATION OF REFERENCE NUMERALS

1 semiconductor laser device

10 single crystal SiC (submount)

11 first surface

12 second surface

13 one surface

14 other surface

15 micropipe

20 base

30 semiconductor laser element

40 a insulating member

40 b fluid object

50 a bonding member

50 b bonding member

60 metal layer

100 jig

What is claimed is:
 1. A semiconductor laser device, comprising: aninsulating single crystal SiC having a first surface, a second surface,and micropipes having openings in the first surface and the secondsurface; a conductive base provided on a side of the first surface ofthe single crystal SiC; a semiconductor laser element provided on a sideof the second surface of the single crystal SiC; and an insulatingmember disposed in the micropipes, wherein the insulating member is alsodisposed on the first surface and the second surface of the singlecrystal SiC in addition to inside the micropipes, and an amount of theinsulating member that is disposed on the side of the second surface ofthe single crystal SiC is smaller than an amount of the insulatingmember that is disposed on the side of the first surface of the singlecrystal SiC.
 2. The semiconductor laser device according to claim 1,wherein gaps are provided in the micropipes.
 3. A semiconductor laserdevice comprising: an insulating single crystal SiC including a firstsurface, a second surface, and micropipes having openings in the firstsurface and the second surface; a conductive base provided on the sideof the first surface of the single crystal SiC; a semiconductor laserelement provided on the side of the second surface of the single crystalSiC; a first conductive member comprising a first conductive bondingmember provided on the first surface of the single crystal SiC; and asecond conductive member comprising a second conductive bonding memberprovided on the second surface of the single crystal SiC and that isinsulated from the first conductive member, wherein a part of at leastone of the first conductive member and the second conductive memberpenetrates into the micropipes, and wherein the micropipes are crystaldefects in the single crystal SiC.
 4. The semiconductor laser deviceaccording to claim 3, wherein a distance between the first conductivemember and the second conductive member is at least 15 μm.
 5. Thesemiconductor laser device according to claim 3, wherein the firstsurface and the second surface of the single crystal SiC are areas inwhich the insulating member is not disposed across the entire area. 6.The semiconductor laser device according to claim 3, wherein the firstconductive member and the second conductive member are insulated fromeach other so that an insulation breakdown voltage is 250 V or higher.7. The semiconductor laser device according to claim 6, wherein adistance between the first conductive member and the second conductivemember is 15 μm or more.
 8. The semiconductor laser device according toclaim 6, wherein a thickness of the single crystal SiC is at least 100μm and no more than 400 μm.
 9. The semiconductor laser device accordingto claim 6, wherein a specific resistance of the single crystal SiC isat least 1×10⁷ Ω·cm.